We use the glass carboy's here in the US. Plastic can acquire hard to clean scratches. As for a conical, I've read that the shoulders of the carboy aren't steep enough for the yeast to slide down for proper dumping.
But hey, for free it's worth a shot>
The glass carboys are heavy and (if you drop them) rather dangerous. I'm currently trying out the 'Better Bottles' which are much the same as the drinks carboys above only made of a better plastic.